Fastening for doors



Jan. 23, 1940. J H, DARBY 2,188,034

FASTENING FOR DOORS Filed Sept. 6, 1938 4 sheets sheet 1 \SLazqfifllgju 4 2 7 K (11 Q 5 1 l4 l5 4 y 7 12 Fig.1. 338' Inventor Jan. 23, 1940. J H, DARBY FASTENING FOR DOORS Fi led Sept. 6, 195a 4 Sheets-Sheet 2 I I I I I I I l I 0 an] guiolg Fig.4.

Fig.5

Jan. 23, 1940.

J. H. DARBY 2,188,034

FASTENING FOR DOORS Filed Sept. 6, 1938 4 Sheets-Sheet 3 Jan. 23, 1940. jHL DARBY 2,188,034

FASTENING FOR DOORS File p 195 4 Sheets-Sheet 4 Inventor Fig.1 3 by w cl. I fltiorney- Patented Jan. 23, 1940 PATENT OFFICE FASTENING FOR DOORS John Henry Darby, Hillmorton, Rugby, England Application September 6, 1938, Serial No. 228,557 In Great Britain March 13, 1937 4 Claims.

This invention relates to fastenings for doors, and particularly vehicle doors.

The invention is of especial application for fastening doors that are fitted with automatically operating closing devices. It will be understood that the ordinary spring-controlled bolts of door fastenings provided with inclined striking faces offer resistance in their retraction in the last stage of movement of the door in closure. The invention has among its objects to avoid this disadvantage and to ensure that doors may always close completely under the operation of self-closing devices.

The invention has further among its objects to enable the door vto be securely fastened without violent slamming and to prevent the door from rattling when fastened.

The invention has further among its objects to provide a door fastening of all descriptions which offers no substantial resistance in the final stage of movement of the door in closure'irrespective of the strength of the spring employed for the purpose of moving the bolts to their outer or operative positions.

The invention has further amongits objects to provide a door fastening with trip mechanism which will ensure that the door cannot be opened without the trip mechanism being set, notwithstanding any variation of clearance that there may be between the free edge of the door and the striking plate mounted on the door frame.

A further object of the invention is to provide a door fastening having trip mechanism in which, if the door is not completely closed, it will be retained in the nearly closed position and will not fly open while the vehicle is in motion.

It is further among the objects of the invention to provide a door fastening foruse in doors fitted with self-closing devices in which the resistance offered in the last stage of movement of the door in closure by a spring loaded bolt is too great to allow complete closure.

The invention also has among its objects to provide a door fastening provided with trip mechanism which will fasten the door tightly against resilient buffering without slamming.

A further object of the invention is to provide a door fastening having trip mechanism-which does not require an undue amount of movement of the control handle and which does not offer an undue amount of resistance to the control handle in the opening of the door.

A further object of the invention is to provide a door fasteningwith trip mechanism in which the door can be slammed shut withoutcausing injury to the lock or door frame when the trip mechanism is inoperative through accident or failure while thedoor is still open.

According to the invention a spring-controlled bolt is provided normally held in the retracted 5 position whereby on the operation of the door self-closing device no substantial resistance is offered in the final stage of movement of the door in closure, but on the door approaching or reaching its closed position the spring-controlled bolt is released so that the door is thus fastened in its closed position immediately upon reaching it, whereupon the operating handle or knob of the door has to be rotated for the retraction of the bolt, which is then held in its retracted position to be again released only on the door approaching or reaching the closed position.

The spring-controlled bolt is thus held in its retracted position by means that are adapted to be released on the door approaching or reaching the closed position.

According to the invention moreover a safety catch which may be in the form of a bolt is provided that is withdrawn on the retraction of the main spring-controlled bolt until the latter is again held, the safety catch being itself independently held in its respective engaged and retracted positions.

According to the invention furthermore, the safety belt is adapted to operate both in the opening and the closing of the door; thus means are provided for controlling the movement of both the bolts, which means. serve to retract the safety bolt. into the inoperative or inward position only after the main .bolt has been first retracted a predetermined distance inwardly, and which are effective to retain the main bolt in the inoperative position while only temporarily rendering inoperative the safety bolt, which is thus adapted to be returned into the operative position to serve as a safety bolt in the closing ,of the door.

Thus the main bolt may normally be pressed outwards into the outer or operative position by means of a relatively strong spring and the auxiliary or safety bolt may normally be pressed outwards into the outer or operative position by a relatively weak spring, the main bolt and the safety bolt being operatively connected so that by the movement of a lever, cam or the equivalent under the control of an operating handle 5 such as the door handle, the main bolt is first retracted or moved inwards to a predetermined extent before the second or safety bolt is moved,

the main bolt being retained in the inoperative position at the 'end of the control movement but the safety bolt being only temporarily retained in the inoperative position and assuming its normal outward or operative position independently of the main bolt under the influence of the relatively weak spring, as for example, when the operating handle is released.

Thus the safety bolt is always in the operative position except when the main bolt is being intentionally retracted by the deliberate operation of the actuating lever and hence the safety bolt not only prevents the door from being unintentionally opened, as for example when the operating handle is accidentally partly turned or rotated, but further acts as a strike bolt which will prevent the door from swinging open even if through incomplete closure the main bolt is retained in its inner or inoperative position.

According to the invention furthermore, the door fastening may be provided as a single spring-controlled bolt which may be formed in two parts, one part under the influence of a relatively strong spring being adapted to be retracted a predetermined distance before the other part under the influence of a relatively weak spring and which in the normal position engages the striking plate is started to be withdrawn, the first mentioned part being retained in the inoperative position by suitable means, as by a spring-controlled detent engaging in a slot in the said part, and the second mentioned part being retained in the retracted position only temporarily and adapted to be returned into the operative position to operate as a strike bolt. Alternatively the second mentioned part may be free to slide in either direction.

The usual apertured plate fitted to the door frame that is adapted for the reception of the spring-actuated bolt of the door fastening may be replaced by a substantially vertically disposed roller that is mounted in a double-armed fitting or bracket secured to the door frame. The roller is preferably made of rubber, or a rubber sleeve is mounted upon a vertically disposed pin or spindle which may advantageously be fixed to or removably secured to the projecting ends of the double-armed fitting or bracket that may be secured to the door frame by means of screws at a position where the usual striking plate is located.

The invention is of general application to the fastening of doors and comprises the constructional features hereinafter described.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which Figure 1 is a side elevation showing the working parts of a door fastening constructed according to the invention.

Figure 2 is a sectional plan view of a modified construction.

Figure 3 is a side elevation corresponding to Figure 2, viewed from the outer side of the door.

Figure 4 is a side elevation of a modified construction in which the main bolt is formed in two parts and is shown in the first stage of opening of the door.

Figure 5 is a view corresponding to Figure 4 showing the bolt at the limit of its travel in the opening of the door.

Figure 6 is a plan view corresponding to Figures 4 and 5 showing a modification of the construction illustrated in these figures with certain parts omitted.

Figure '7 is a side elevation of a modified construction of the latch or bolt shown in Figures 4, 5 and 6.

Figure 8 is a side elevation of a modified construction of the door fastening according to the invention.

Figure 9 is a side elevation corresponding to Figure 8 showing positions of the actuating lever during the opening of the door.

Figure 10 is a side elevation of a modified construction of the lock illustrated in Figures 8 and 9.

Figure 11 is a side elevation of a further modified construction of the door fastening according to the invention, and Figure 12 is a side elevation of a further modification.

In carrying the invention into effect according to the construction illustrated in Figure l of the accompanying drawings the door fastening mechanism ismounted as usual within a box casing I that is adapted for application upon or within the door, there being provided a complementary fitting 2 upon or within the door frame. The door fastening mechanism comprises a spring-controlled striking bolt mounted within the casing l to slide outwardly on release through a hole in the striking plate of a shape corresponding to that of the transverse crosssection of the bolt. The bolt is advantageously formed at its front endof a slightly conical, tapered or other similar shape, while at its rearward end 5 it advantageously extends downwardly. Between the downwardly extending part of the bolt and the rear wall of the casing opposite in position to the striking plate, a V-shaped spring 4 may be conveniently provided by means of which the bolt is normally acted upon by the spring in order that on release the bolt may be impelled forward to engage at its forward end the complementary fitting 2 upon or within the door frame, whereby the door is thus fastened or held closed in its closed position. A knob or handle spindle 6 is mounted in position beneath the main part of the bolt and the spindle may extend at each side of the door for the reception of the handles or knobs. The spindle may carry in a central position within the casing an arm or arms I which on the rotation of the spindle engage the adjacent downwardly extending part 5 of the bolt, so that on rotation of the spindle for example in an anticlockwise direction the bolt may be retracted, to be held in its retracted position.

For holding the bolt in its retracted position a retaining arm 8 is provided which may be conveniently mounted above and. normally parallel with the bolt, and the arm at one end may be pivoted on the wall of the casing while the opposite end of the arm may extend through a hole or recess of a corresponding form in the striking plate, the arm being so placed that on the door approaching its closed position the outwardly extending end of the arm will make contact with some part of the complementary fitting 2 on or within the door frame, whereby the bolt 3 will be released and its forward end passed through the striking plate to engage with the complementary fitting 2. The pivoted retaining arm 8 by which the bolt 3 is held in its retracted position may be provided with a downwardly extending part 9 adapted to enter a transverse slot III which may for example be provided on the adjacent front face of the main part of the bolt to register with the downwardly extending part 9 as the bolt approaches or reaches its completely retracted position. Thus it will be understood that on the door approaching its closed position the pivoted retaining arm 8' will be moved outwardly '(against theaction of a leaf or other spring ll tending to maintain it in its engaged position) by contact with the complementary fitting 2 provided upon or within the door frame whereby the bolt 3 is thus released and the door fastened in its closed position.

Withinthe box casing I and beneath the bolt 3 a safety catch I2 is provided that is adapted to follow the respective movements of the bolt 3, the safety catch being curved at-its upper end I3 and provided on one face with two outwardly extending pins or parts I4, I I spaced apart, between which is disposed a downwardly extending pin or part I5 carried by the bolt 3. The two outwardly extending pins or parts I4, I I on the safety catch I3 and the downwardly extending pin or part I5 carried by the bolt serve as means by which the safety catch I3 is caused to follow the movements of the bolt 3 without connection of the bolt to the safety catch under conditions in which the safety catch is independently held in its respective positions. The

safety catch I2 may be provided as a normally upstanding member conveniently formed of a bar of metal and pivotally mounted at IE on the vertically disposed foundation wall of the box casing I and extending downward beyond the v pivot pin to an acute angled form presenting at the lower end of the safety catch symmetrically free end of a leaf spring I8 mounted'on the lower wall of the box casing ,I. The free end of the leaf spring is so formed that the lower end of the bar of the catch I2 in its extreme positions comes to lie on the opposite sides thereof, whereby the bar completes its movements in both directions under the eifect of the leaf spring I8 which also serves to maintain it in those positions. Thus it will be understood that upon the retraction of the bolt 3 from the position illustrated in Figure 1 to a position-in which the slot I0 is carried slightly beyond the detent 9 the pin I5 will strike against the-pin M whereby the catch I2 is caused to assume a position on the opposite side of the spring I8. The detent 9'on release of the control handlewill fall under the i action of the spring II into the slot I9 andthe bolt and the safety catch will be held in the fully retracted position so that the door can be opened. On the closing of the door the pin I5 will strike against the pin I4 whereby the catch I2 will assume its normal position as illustrated in the drawings. It will be understood that one end of the curved arm I3 of the safety catch I2 will on the release of the bolt 3 be projected through a hole of corresponding form in the catch plate and in the complementary plate or fitting 2 applied on or within the door frame and that the safety catch I2 will also follow the bolt 3 on its retraction. I

It will furthermore be understood that the outer end of the pivoted retaining arm 8 may be positioned near the front face of the casing i so that the outer end of the arm may be actuated to cause its lateral movement'for the release of the bolt 3 when the bolt is approximately in alignment with a corresponding hole in the complementary plate or fitting 2 applied upon or within the door frame. It will however be understood that the outer end of the pivoted retaining arm 8 maybe otherwise disposed in relation toa plate or fitting 2. I 'In carrying the invention into effect according to the modified construction as illustrated in Figures 2 and 3 of the accompanying drawings the main bolt co-operates with the second or safety bolt so that on rotation of an operating lever such as the door handle the second or safety bolt is retracted only after the main bolt has been moved inwards a predetermined distance to-v wards the inoperative position. On the completion of the opening movement at the end ,of the inward travel the mainbolt isretainedin the inoperative position until it is again released in the closing of the door, the second or safety bolt at the end of its inward travel being however disconnected from operative engagement with the main bolt on the release of the operating handle and returning to the operative position in which position it will be adapted to engage the striking plate of the door on the strikebolt' principle and so will be effective to prevent the door from swinging open.

In the construction illustrated themain bolt I9 and the second or safety bolt are provided with striking plates 2I and 22 respectively mounted in the door frame 26. The main bolt I9 has secured thereto an adjustable projecting part 23 which is adapted to engage in the rearward movement of the main bolt I9 into the inoperative position with a co-operating laterally projecting member or detent 24 pivotally mounted at 25 on the second or safety bolt 29 to rock in a plane transverse to the planelof movement of the bolts I9 and 20. The safety bolt 20 is as shown advantageously mounted in a position adjacent the main bolt I9.

The bolts I9 and 29 may be formed at their projecting ends with inclined faces in the usual manner. to engage with the striking plates. 2i and 22 respectively which are mounted in the door frame 26. I

The laterally projecting part 24 pivotally mounted at 25 on the safety bolt 29 is retained in position in the path of the projecting part 23 under pressure of a leaf spring 21 or the equivalent secured on the bolt 20.

The main bolt I9 is held in the forward position as shown in Figure 2 of the drawings under the influence of a helical spring 28 mounted at or near the rear end of the bolt on a cylindrical extension of the bolt and bearing at one end against a fixed stop 29 and at the other end against a flange or collar 39 on the bolt I9.

.The bolt I9 is adapted to be moved into the retracted inoperative position by means of an arm 3| secured on to the operating spindle 32 of the door handle 33 which arm engages with a laterally projecting part 34 formed on the main bolt I9.

A transversely extending arm35 is secured to the spindle 32 which is effective to release the projecting part 24 mounted on the safety bolt 29 from engagement with the'adjustable projecting part 23 on the main bolt I9 on the return rotational movement of the handle 33 after the completion of the opening movement as hereinafter described.

,Trip mechanism is mounted on the top face of the main bolt comprising a lever 39 pivoted at or near a central position at 3! to project in the usual manner forwardly of the bolt so as to engage with the striking plate at 38, and rearwardly so as to engage with a stop 39 provided on the main boltin itsretracted or inoperative.

corresponding contact face on the complementary position. A leaf spring 40 secured on to the side wall of the bolt casing is provided to bear against the rearwardly projecting end of the lever 36 so that it is caused to bear against the bolt l9 so as to engage the stop 39 except in the position, as shown in Figure 2 of the drawings, in which the door is closed.

The safety bolt 26 is held in the operative position under the influence of a helical spring 4| secured in any suitable manner at 42 to the forward part of the casing and to the bolt by the projection 43.

The spindle 32 of the control handle of the door is provided with a coil spring-44 which serves to return it into its original position on release of the door handle 33 at the end of the opening movement of the door and simultaneously causing engagement of the arm with the projection 24.

In operation, on rotation of the door handle 33 the projecting arm 3! engages with the projecting part 34 on the main bolt l5 and is effective to withdraw the bolt I 9 towards the inoperative position, where it is retained by means of the trip mechanism, the inwardly projecting part of the lever 36 engaging with the stop 39 mounted on the main bolt l9 and the lever 36 being pressed against the bolt 19 by the leaf spring 40. After a predetermined extent of movement of the main bolt I9 the adjustable projecting part 23 provided thereon engages with the laterally projecting member 24 pivotally secured at 25 on the safety bolt 20, thus serving to withdraw the safety bolt 20 into the inoperative position shown in dot and dash lines in Figure 2 of the drawings. On release of the operating handle 33 the spindle 32 is rotated to return into its original position under the influence of the spring 44 and in so doing causes the radially extending arm 35 mounted thereon to engage with the laterally projecting member 24 pivotally mounted on the safety bolt and moves it against the pressure of the leaf spring 2'! which normally retains the member 24 in the plane of the adjustable projection 23 out of this plane, so as to permit the safety bolt 20 to move forward under the pressure of the spring 4! into the operative position, so that it may operate as a strike bolt.

In the closing of the door the forwardly projecting part of the lever 36 of the trip mechanism engages at 38 with the striking plate mounted on or within a complementary fitting upon or within the frame and operates to release the mainbolt l9 which is shot forward into the operative position under the influence of the helical spring 28 mounted at the rear end thereof.

It will be understood that the bolts maybe provided with inclined faces at the free ends so that should the lever 36 fall to retain the main bolt in its inoperative position the door may still be adapted to be closed on the strike bolt principle.

In carrying the invention into effect, according to a modified construction as illustrated in Figures 4 and 5 of the accompanying drawings, the fastening may comprise a single bolt element formed in two parts disposed in alignment. The forward part of the bolt 45 is retained in the operative position until released by the rear part 46 on the latter reaching the limit of its inward travel, or a predetermined extent of its inward travel. The forward part 45 of the bolt projects in the closed position of the door as shown in Figure 4 of the drawings to engage the striking plate mounted in a complementary fitting upon or within the door frame and is connected to the rear part 46 of the bolt by a relatively weak helical spring.

The part 46 is formed with a rearward cylindrical extension 48 on which is mounted a relatively strong spring 49 bearing at one end against the shoulder 56 formed between the extension 48 and the part 46 and at the other end against a fixed stop 5|. The rear part 46 is adapted to be retracted in the opening of the door by means of an actuating lever 52 mounted on the spindle 53 of the door handle, the lever 52 engaging a stop 54 secured on the part 46 of the bolt so that on rotation of the door handle the part 46 is retracted into the position shown in dot and dash lines in Figure 4 of the drawings. The part 46 is adapted to be retained in this position by means of a spring arm or detent 55 projecting downwardly from a lever 56 forming part of the trip mechanism and adapted to engage in the fully retracted position of the part 46 in a slot 5'! formed in the part 46. The lever 56 is pivotally mounted at the rear end at 58 and is held under the influence ofa leaf spring 59 secured to the casing in a position to bear against the side of the opening in the casing and so that the member 55 bears against the part 46 of the bolt. At the forward end the lever 56 projects from the opening in the casing of the fastening for engagement with a complementary fitting in the door jamb or pillar on the closing of the door.-

The front part 45 of the bolt is restrained from movement during the retraction of the rear part 46 by means of a knee-lever 60 which is pivotally mounted on the wall of the casing and is adapted to bear under spring pressure with the forwardly directed arm, in the closed position of the door as shown in Figure 4 of the drawings, against a stop 6| provided on the front part 45. To the rear of the lever and substantially in alignment is mounted a similarly formed lever 62 operated under spring pressure and which is adapted to bear with its forwardly directed arm on the rearwardly directed arm of the lever 60- in the position shown in Figure 4, the rearwardly directed arm of the lever 62 projecting into the path of the part 46 of the bolt in its retraction movement.

In operation rotation of the door spindle 53 causes the lever52 to withdraw, the part 46 of the bolt inwardly by engagement with the stop 54 into the position shown in dot and dash lines in Figure 4 of the drawings. In the final stage of movement the rear face of the part 46 at the upper edge will abut against the rearwardly directed arm of the lever 62 causing the front arm of this lever to bearon the rearwardly directed arm of the lever 60 and thus to cause the front arm of the lever 66 in a pivotal movement to be disengaged from the stop 6|, thus permitting the front part 45 of the bolt to follow the rearward movement of the rear part 46 under the influence of the spring 4'! as shown in Figure 5 of the drawings.

The rear part 46 is retained in the fully withdrawn position by engagement of the spring arm or detent 55 in the slot 51. The latch is caused to return into the operative position on the closing of the door by means of the trip mechanism comprising the lever 56 under the influence of the spring 59, the projecting end of which lever engages the edge of the pillar of the door frame thus causing the spring arm or detent 55 to be raised from the slot 51 and the return of both parts of the bolt into the original operative posi- .tions under. the influence ofthe spring 49. Thus it will be understood that the fastening will ensure practically no resistance in closing inthe final stages of closure, irrespective of the strength of spring employed to return thebolt into its operative or outward position. Moreover, irrespective of the clearance between door and pillar, the door cannot be openedeither inadvertently or intentionally-until the bolt has been retracted far enough to permit its retention by the engagement of the spring arm or detent 55 in the slot 51. If however, for any. cause such as breakage or failureof the retaining mechanism, the bolt should resume its outward operative'poe sition after the door has been opened, it is not possible in the construction hereinbefore with reference to Figures 4 and 5 of the drawings, for the bolt to operate as a strike'bolt, as theforsward part 45 of the bolt is held in its outward -of;1novementin a direction position by the lever 66 and stop 6i and can only be released by the full retraction of the rearward part 46 of the bolt.

Means may be provided to ensure that the lever 60 is disengaged from the stop 6lduring such time as the door is open. Such means are illustrated in Figure 6 of the accompanying drawings.

The forwardly directed arm of the lever66 is pivoted at 62 so that the arm may be capable at right anglesto its movement about its'pivot. The forwardly directed arm of the lever 60 is connected by a link 63 to the lever 56 in such'manner that when the door is closed and the lever 56 pressed outwards against the pressure of the spring 59 by reason v of its contact with its complementary fitting 64 secured on the door pillar or jamb, the link 63 maintains the lever 56 in line with the stop 6|; but when-the door is opened the lever 56 moves under the influence of the spring 59 intoa positiontowards the bolt as shown in dotted linescausing the pivoted forwardly directed arm of the lever 60 to move laterally out of engagement with the stop 6| into the dotted line position. u

In Figure 'l is shown a modification of the construction illustrated in Figures 4, 5 and 6, in which certain of the parts have been omitted. The bolt is formed in two parts, a front part and a rear part 46, the rear part 46 being under the influence of a spring 49 as in the construction v shown in Figures 4, 5 and 6. In the present construction also the front part 45 of the bolt is caused to follow the rearward movement of the part 46 on the rotation of the actuating lever 52 after a predetermined extentof movement of the part 46 and as in the construction described with reference to Figures 4, 5 and 6, the part 46 is retained in the retracted position by means of a'spring pressed member or detent controlled by the trip mechanism, which member is adapted to engage, in the retracted position of the part '46, in a slot provided in the part 46. The part 45 is connected by a relatively weak spring 65 to the actuating lever 52 and the actuating lever is connected by means of a spring 66 to the casing so that on release of the door handle the lever 52 will return into its normal position. A springc'ontrolled spindle 61 is mounted in bearings longitudinally of the front part 45 of the bolt, being under the control of a spring 68 and provided with a buffer 69 at one end. The actuating lever 52 is adapted in its rearward movement on release of the control handle to bear against the buffer. 69 causing thefront part 45 of the bolt to return into the forward operative position in whichposition it is free to engage the striking plate on the outer frame of the door as a strike bolt. The inward, movement of the part 45 as it overrides the catch or catches of the striking plate will be absorbed by the spring 68 which is for the purpose advantageously provided relatively weaker than the spring 66. The actuating lever 52 and therefore the handle will not be affected.

The rear part 46 is adapted to be returned into the operative position to bear against the part 45 on the closing of the door under the pressure exerted by the spring46 through the agency of trip mechanism of the kind for example as described in connection with Figures 4 and 5 of-the drawings or as described with reference to Figure 6 of the drawings.

Owing to therelative weakness of the spring 68 the resistance to closure will be negligible.

Figures Sand 9 illustrate a modified construction of the door fastening illustrated in Figures 2 and 3. In this construction the main bolt 16 l is under the-influence of a relatively strong spring H. and the safety bolt i2 is under the influence of a relatively weak spring 13. The spindle of the door handle M has mounted thereon actu-- ating arms-or levers 15 and 16 which are adapted to bear respectively against projections H and 18, themselves mounted respectively on the main bolt 16 and the safety bolt 12. The projecting part 11 on the main bolt in the normal operative position of 'the bolt is disposed relatively near the arm 15 whilst the projecting part 18 on the safety bolt is relatively distant from the arm 16, so that the main bolt will commence to be withdrawn as soon as the actuating spindle 14' commences to rotate while the safety bolt 12 will not commence to be withdrawnuntil the main bolt 'Hlhas been retracted a predetermined distance. Thus it is ensured that the main bolt 16 is withdrawn a predetermined distance to a position in which it is retained by engagement ofa lever or detent engaging in a slot in the manner as 'hereinbefore described, before the safety bolt has been retracted a sufficient distance to clear the striking plate and permit the door to be opened. As the projection i8 is a greater distance than 'the projection H from the actuating spindle 14, the safety bolt 12 will move relatively faster than the main bolt 16 and-therefore the main bolt 16 will be retracted for a less distance beyond the position essential for its retention than would have been the case had the projections 11 and 18 been equidistant from the actuating spindle. Furthermore according to this arrangement a greater leverage will be available to withdraw themain bolt 16 against its relatively strong spring H. On retention of the main bolt-l6, in the inoperative position the release of the door handle will permit the safety bolt [2 to return to the operative position under the influence of the spring 13 to engage the striking plate as astrike' bolt.

The functions of the two arms 75 and 16 may be combined in one arm or lever to engage both the projecting parts 11 and I8 and such a con struction is illustrated in Figure 10, in which the main bolt 86 is under the influence of a relatively strong spring 8| and the safety bolt 82 vided mounted on the spindle 85 of the door handle. The lever 84 is formed of aparticular shape having a curved contact face 86 which first engages against the projection formed on the main bolt 89 to withdraw it into a position in which it is retained by trip mechanism of the kind as hereinafter described with reference to the construction illustrated in Figure 11, and in the final stage of its movement to engage With a substantially straight contact face 8'! against the projection formed on the safety bolt 82 to withdraw it into a position in which it is free of the striking plate so that the door may be opened. On the door being opened and the handle released the main bolt 89 will be retained in the inoperative position by the trip mechanism before referred to while the safety bolt will be free to resume its normal outward operative position under the influence of the spring 83 and to engage the striking plate in closing as a strike bolt. The actuating spindle 85 of the door handle may in this case advantageously be provided with a separate spring for returning it into its normal position on the handle being released.

The foregoing arrangement described with reference to Figure 10 may be adapted for use in a trip-lock having a single bolt formed in two parts as hereinbefore described with reference to Figures 4, 5, 6 and 7, the two parts of the bolt depending on actuating levers or a single actuating lever for their inward movement into the inoperative position and upon a relatively weak spring (in the case of the forward part) and upon a relatively strong spring (in the case of the rear part) for their outward movement, the rear part being adapted to be retained in its retracted position in the manner as here inbefore set forth, while the forward part is free to move outwards on the release of a handle and to engage the striking plate as a strike bolt. Thus it will be understood that strike bolt having a single bolt capable of engaging the catch or catches of the striking plate is provided, the resistance to which engagement will be slight owing to the lightness of the spring returning the safety bolt, and that in addition to the safety bolt a main bolt having a strong returning spring is provided which is not adapted to engage the striking plate but which is adapted to be released in the final stage of closure and to force the forward part of the bolt firmly home.

A modification of a fastening according to the invention in which the." principle adopted in the construction illustrated in Figures 8, 9 and 10 is utilised, is illustrated in Figure 11. Referring to the drawings the main bolt 88 is under the influence of a spring 89 and the safety bolt 99 under the influence of a spring 9|. The bolts 88 and 99 are disposed substantially parallel and adjacent, the safety bolt 90 being formed at the forward end with an enlarged part to engage the striking plate on the door frame which part extends downwardly to form a shoulder 92 against which the main bolt 88 is adapted to bear in the closing of the door. The main bolt 88 is provided with a projection 93 and the safety bolt 90 with a projection 94 against which an actuating lever 95 mounted on the spindle 96 of the door handle is adapted to bear in the opening of the door. The contacting face of the actuating lever 95 is formed curved and the relative positions of the projecting members 93 and 94 are so determined that the lever first engages the projection 93 on the main bolt 88 to withdraw the bolt into the position in which the spring arm or detent 91 secured on the trip lever 98 engagesin the slot 99 formed in the main bolt, and in its subsequent movement bears against the projection 94 on the safety bolt 99 which is retracted into a position to withdraw its forwardly projecting end from the striking plate and to permit the door to be opened. On release of the actuating lever 95 the safety bolt 90 returns into the operative position under the infiuence of the spring 9| and when the door is closed the trip lever 98 is effective to remove the detent 91 from the slot 99 in the main bolt 88 and to permit the bolt 88 to move forwardly into the operative position under the influence of the spring 89 so as to abut against the shoulder 92 formed on the safety bolt 90 and thus to drive this bolt firmly home. Alternatively the relatively weak spring 9! may be omitted and the bolt 9 provided free to slide in either direction.

According to a further construction (Figure 12) a spring loaded safety bolt is provided that is advantageously pivoted whereby its free end is capable of movement in a vertical plane.

A main bolt is provided that is adapted to be retracted against the action of a spring and held in its retracted position by a detent formed integral with a trip lever, the trip lever being formed with a hole to fit loosely over a control spindle. In-itslast stage of movement an actuating lever mounted on the control spindle strikes against an'inclined edge of the safety bolt whereby its free end is raised from a recess provided on or within the door frame to permit the door to be opened.

On release of the control handle the main bolt is held retracted but the safety bolt is free to resume its normal position so as to engage the recess upon the closing of the door. The free end of the safety bolt is advantageously provided with an inclined face whereby it may ride over the lateral edges of the recess, which recess may also be provided with a correspondingly inclined face.

I claim:

1. A door fastening including a member formed in two parts disposed in axial alignment, one of which parts is adapted to operate as a safety bolt to engage the striking plate mounted on the door frame, and the other part being adapted when the door is opened to be held retracted against spring pressure by means of trip mechanism and to be released by said mechanism engaging the striking plate when the door is in the fully closed position to ram the first part home.

2. A door fastening including a member formed in two parts disposed in axial alignment, one of which parts is adapted to operate as a safety bolt to engage the striking plate mounted on the door frame, and operating mechanism for withdrawing the other of said parts into a retracted position when the .door is being opened before the first part is moved, so that said other part is held retracted by means of trip mechanism and is releasable by said mechanism when the door is in the fully closed position to ram the first part home.

3. A door fastening including a member formed in two parts disposed in axial alignment, one of which parts is under the influence of a relatively weak spring and is adapted to operate as a safety bolt to engage the striking plate mounted on the door frame, operating mechanism for withdrawing the other of said parts into a retracted position, said other part being under the influence of a relatively strong spring and adapted to be retained against spring pressure by means of trip mechanism operable when the door is opened and to be released by said trip mechanism when the door is in the fully closed position to ram the first part home.

4. A door fastening according to claim 3, in

which that part of the member which is adapted to operate as a safety boit'and engages the striking plate is free to slide in either direction without being influenced by a spring or the like and the other part of the member is under the 5 influence of a spring.

JOHN HENRY DARBY. 

